This invention relates to the field of automotive control and location determination.
Automobile parking lots have grown in size due in part to the development of large department stores and shopping malls. Often times a driver of an automobile parks in the large parking lot for shopping or other business. When the driver returns to the parking lot the driver may not be able to remember the location of the automobile and thus can waste a significant amount of time hunting for the automobile in the large parking lot. Modem automobiles often are manufactured with a key having an attached remote transmitter that allows the driver to remotely lock or unlock the automobile while the automobile is within a limited wireless transmission range. Such remotes are also available on an after market installation basis. Often, the automobile will sound a horn, flash exterior lights or other audio/visual alert when the remote transmitter is activated in the vicinity of the automobile, thereby facilitating location of the automobile within the limited range. Unfortunately, this limited range between the transmitter and automobile and the limited range of the automobile""s audio/visual alert only allows a driver to pinpoint the automobile location if the automobile is close to the driver. This method is of very little use in locating an automobile in a very large parking area or far from the driver.
The advent of global positioning systems (GPS) has allowed determination of a location virtually anywhere on the surface of the planet where the GPS signal can be received. However, consumer GPS devices are usually general purpose having a complex user interface an expensive display. Furthermore, many consumer grade GPS receivers have inaccurate pinpoint location and can only guide to a location which is close, but are incapable of pinpoint accuracy. Furthermore, GPS devices typically operate continuously and consume a large amount of power, thus rapidly depleting batteries used to power portable GPS receivers.
Thus, what is needed is a simple portable device for locating an automobile which takes advantage of the benefits of both GPS and remote transmitter location determination without rapidly depleting batteries powering the device.